The objective of this work was to investigate the potential use of pulsed electric field (PEF) in combination with osmotic dehydration (OD) as a pre-freezing step and to evaluate the effect on quality characteristics and shelf life of frozen kiwifruit. Peeled kiwifruit was subjected to PEF (1.8 kV/cm), sliced and treated in OD-solution (containing glycerol, maltodextrin, trehalose, ascorbic acid, calcium chloride, citric acid, sodium chloride; 1/5 (wfruit/wsolution)) for 30 and 60 min at 35 °C. Combined, PEF only and OD only treated samples as well as nontreated and blanched (80 °C, 60 s) samples were frozen and stored at constant (-5, -10, -15, -25 °C) and dynamic temperature conditions (-18 °C-3 d, -8 °C-2.5 d, -15 °C-3 d). Quality of frozen samples was evaluated by means of drip loss, colour, texture, vitamin C and sensory evaluation (1-9 scale); and shelf life (SL) was calculated. Nontreated and blanched samples presented high drip loss and tissue softening (instrumentally measured as Fmax decrease). The tissue integrity was well retained in all osmotically pretreated samples. PEF pretreatment caused increase of fruit whiteness (increase of L value) and yellowness (a and/or b value increase); SL calculation was based on colour change. All OD samples had high vitamin content (24.6 mg/100 g fresh material compared to 138-154 mg/100 g osmodehydrated material); PEF led to 93% (of the initial) vitamin retention; blanched samples showed the lowest retention (86.9% of the initial) (criteria for SL calculation). OD and combined PEF-OD treatment increased the shelf life of frozen kiwifruit (up to 3 times; based on sensorial criteria). The developed kinetic models for colour change, vitamin loss, and sensory quality deterioration were validated at dynamic temperature conditions. PEF pretreated OD (at significantly shorter time, 30 min compared to 60 min) kiwifruits retained optimum quality and sensory characteristics. PEF and OD could be used as a preprocessing step of good quality, longer shelf life kiwi sliced frozen products.

What is the profile of Food Engineering education in Brazil? Are we following the contemporary professional renewal trend? Driven by these questions, the present study analyzed data regarding 21 academic courses, which represent approximately 22% of the total bachelor’s degree in food engineering courses offered in the country. Samples were defined considering a Brazilian annual ranking of undergraduate programs: very good (four stars) and excellent (five stars). Next, information was recovered from both the Brazilian Ministry of Education and institutional homepages of each analyzed program. The results suggest that food engineering programs exhibit relative identity, naturally due to their history and the path of each program and their faculty, shaping particularities in how fields of knowledge are constituted, in addition to their representativeness in the total workload of the program. However, initial analysis is suggestive regarding understanding that Brazil is not properly doing its homework, based on global movement, concerning food engineering education. The need to rethink Brazilian technical education, without culminating in additional workload, is emphasized, not only regarding new materials and technologies for learning and teaching, but also in terms of bringing a human and market approach. The achievement of this complex goal seems to be provided by the encouragement of student associations, transversal learning processes, and learning experiences outside the classroom as a means of improving undergraduate programs and human resources.

The objectives were to evaluate the properties of refined (ROO) and extra-virgin olive oil (EVOO) in their natural state (fresh) and after heating, while comparing them with each other and with refined soybean (SBO) and refined sunflower seed oil (SFO). The methodology was designed to simulate, in controlled laboratory conditions, the home-frying process, while evaluating fatty acid profile (fatty acid methyl esters were separated by gas chromatography), concentration of phenolic compounds (Gallic acid dosage), antioxidant activity (DPPH), and production of polar compounds (thin layer chromatography) before and after heating to 200 °C for six minutes. It was observed that, before and after heating, SBO and SFO are rich in polyunsaturated fatty acids (FA) and ROO and EVOO are rich in monounsaturated FA. Fresh or heated, ROO and EVOO do not have trans FA, which are present in SBO and SFO, and increase in SBO after heating (+ 32.8%). The concentrations of phenolic compounds are always higher in olive oils, despite the decrease that occurs after heating (-7.5% in the ROO and -24.6% in EVOO). Antioxidant activity is greater when olive oils are fresh and remains present in EVOO after heating. The concentration of polar compounds was similar for all oils after heating. In conclusion, ROO and EVOO are the richest in monounsaturated FA even after heating, with no production of saturated or trans FA. Despite losing some antioxidant activity, heated EVOO remains richer in monounsaturated FA than ROO, SBO and SFO in the fresh version. All oils suffer similar rates of degradation.

Dairy yogurts are common food products consumed by people all over the world. Due to the simple process, many people have made their own natural yogurt at home. The fermentation due to the starter culture causes the textural properties of dairy yogurt. However, the literature is surprisingly scarce on the topic of starter culture interactions in the development of textural properties of dairy yogurt. This study investigated the interaction effect of three common starter cultures, Lactobacillus acidophilus, Lactobacillus bulgaricus and Streptococcus thermophiles, on the viscosity of homemade yogurt. Using Design Expert software, a 10-run mixture model experiment was designed to examine the textural properties developed by single or multiple inoculation of these starter cultures. All yogurt formulations reached the isoelectric point of milk and had pHs in the range 3.97 to 4.32. Yogurt formulations with L. acidophilus and S. thermophilus resulted in viscosities which were similar to commercial yogurt viscosity (1.77 Pa·s), while L. bulgaricus resulted in yogurt with a lower viscosity. Based on the mixture model, L. acidophilus had most influence on the yogurt viscosity, followed by S. thermophilus and L. bulgaricus. In conclusion, L. acidophilus can be used as a single starter culture or combined with other starter cultures to develop high viscosity homemade yogurt. A Combination of S. thermophilus and L. acidphilus can also be used to develop high viscosity yogurts. However, L. bulgaricus should not be inoculated alone or become a dominant ratio in multiple starter culture inoculation as it will decrease the overall homemade yogurt viscosity.

Alcoholic and aqueous extracts were obtained from red sweet pepper (Capsicum annuum L.) by different methodologies to evaluate their cytotoxic, antioxidant and antimicrobial properties. Alcoholic extracts (MFP, MSd, SFP, SDP, SSd) from fresh red sweet pepper (FP) and dry pulp (DP) and seed (Sd) were obtained by maceration (M) and Soxhlet (S) equipment using methanol as extraction solvent; whereas aqueous extracts (LFP, LSd) were obtained by decoction followed by lyophilization (L). Human tumoral cell lines from breast (MCF-7 and SKBr3), prostate (PC3) and cervix (HeLa), and fibroblasts (as control) were used to determine the cytotoxic properties by the MTT assay. Antioxidant and antimicrobial properties were determined by DPPH and disc diffusion method, respectively. The extracts SDP and SFP showed the higher cytotoxic activity. The SDP extract had a significant (P < 0.05) in-vitro effect on HeLa (1.9 ± 1.4 µg/mL) and PC3 (< 1 µg/mL) cells with a moderated impact on fibroblasts (26.1 ± 1.2 µg/mL); whereas, SFP had a significant (p < 0.05) effect on MCF-7 cell line (2.1 ± 1.2 µg/mL) with a moderated impact on fibroblasts (25.9 ± 1.0 µg/mL). The higher antioxidant activity was found for MFP (80.3 ± 0.2%) and SFP extracts (75.5 ± 0.5%). Mild antimicrobial activity was only observed for alcoholic extracts. The results showed the potential of red sweet pepper (C. annuum L.) as a source of antioxidant and cytotoxic compounds, and suggest the need of further studies to isolate and characterize the bioactive compounds that impart those properties. 

Many minimally processed foods depend on a combination of inhibitory factors to reduce the hazard of foodborne illness. Therefore, inactivation of Listeria innocua was studied according to a 24 factorial experiment designed to draw conclusions about temperature (52.5 °C and 65.0 °C), pH (4.5 and 7.5), water activity (aw=0.95 and 0.99) and solute type (NaCl and glycerol) effects. Three different recovery media were used to assess injured cells. Survival data were fitted with a Gompertz-based model and kinetic parameters (shoulder, maximum inactivation rate – kmax, and tail) were estimated. Results showed that shoulder was affected by temperature, pH and combined effects; kmax was influenced by all factors and their combinations; and tail was affected by aw, temperature and aw/pH combination. Results demonstrated the potential occurrence of microbial cross-protection survival techniques between the various stresses, e.g. heat and osmolarity. Indeed, this work clearly established that, to avoid hazards, Listeria inactivation must be evaluated with a maximum of environmental factors that undergo alterations. Only thus, appropriate food preservation treatments can be developed and consequently, the safety of food products can be assured.

The aim of this study was to optimize the processing parameters of pulse mode microwave-vacuum drying of germinated green and red lentils (CDC Greenland and CDC Maxim) and investigate the changes in their total phenolic content (TPC), total antioxidant activity (TAA) and In-vitro starch digestibility (SD). The lentils were germinated for 5 days and dried by a pulse mode microwavevacuum method, using 2 s to 8 s out of 10 s pulsed mode at 2000W microwave power and varying the vacuum pressure level between 15 and 45 kPa. In-vitro starch digestibility increased significantly with increased microwave power level. The TPC and TAA appeared to vary distinctively in the two varieties of selected lentils. Vacuum pressure levels did not significantly (p>0.05) affect any responses. Green lentils could be dried at 8 s microwave power and 45 kPa vacuum pressure and red lentils could be dried at 5.5 s microwave power and 42.19 kPa vacuum pressure. The microwave-vacuum drying showed great potential for the drying of germinated lentils. 

The molecular structure of Traditional Balsamic Vinegar (TBV) undergoes shear-induced and timedependent jamming transitions due to the high solute concentration and self-assembling phenomena of high molecular size melanoidins with very-long relaxation times (12 years at least or more than 25). The purpose of this work was to perform a descriptive and quantitative evaluation of relationships between rheological properties, vinegar composition, and perceptual assessment of sensory properties according to the official sensory procedure. With this aim, vinegars having quality traits matching legal requirements for the PDO designation were analyzed for their reducing sugars (glucose and fructose), volatile acidity, fixed acidity, pH, Brix degree, and density as well as for their flow behaviour and dynamic viscosity over a wide range of shear rates. Results showed that flow behaviour of TBV was affected by jamming properties over wide-scale ranges of shear rate producing flow instability below a shear rate of 60 s−1 . Homogeneous, continuous flow was found at medium-high shear rates with thickening and/or thinning traits. A common onset for the structure scaling was mathematically estimated to occur close to when the density was 1.32 gmL−1 . Comparative analysis of rheological, compositional and sensory properties suggested that the colloidal jamming of the vinegar melanoidins dominated the total olfactive and gustative stimuli, and determined the classification of the vinegars that had a higher dynamic viscosity but more homogeneous flow as being of the highest commercial quality category. A robust statistical model was proposed encoding for the top-down decision-making process for quality assignment according to the official sensory procedure, using composition and flow properties as predictor variables.